My friend is in an abusive relationship. What do I do?

Shes 19 years old and thinks shes in love with a guy. He's really rich and basically buys her whatever she wants. I mean WHATEVER SHE WANTS! He went to London and called me to sneak a peak into her closet to find out what her size dresses she wears and came back with 30 outfits just for her and more jewelery than I've had in my entire life! She comes from a single mother household (her dad died when she was 10) and they were always sort of humble. He gives her so much attention (takes her to fancy restaurants every day, gave her his car when his dad bought him a new one, and a laptop, blackberry, and iphone for her birthday). They've been dating for a year and she says she loves him but they argue every single week over her talking to other men. Not flirtatious talking but rather "whats the chapters included on the final?" type talking. He told her that shes not ALLOWED to talk to other men unless he knows them and if any male tries to talk to her, she shouldn't respond. He then ordered her to go down her facebook friends list with her and he would tell her whether or not shes still allowed to talk to them. She refused and he ignored it and he got pissed! He yelled at her as to why she wants to talk to other guys and went on a rampage around the house. This happened quite a few times but they always made up but this issue would come up every month or so and it would end in her texting me about how pissed she made him and how immature he was being. They're both college students so obviously they need to talk to the opposite sometimes but he tells her shes not allowed but he talks to whoever he wants because he's a guy "and its different" for them. One day after one of their fights, she texts me at 2 AM (after he dropped her off at home) with her typical anger filled message calling him childish, immature, etc. Then at like 4 AM he called her to talk and took her back to his condo in the downtown of the nearest major city to our town so they can talk it out. They talked and worked it out as usual but then she went to the bathroom and when she came out he threw an ashtray at her but luckly it hit the wall behind her and he started to yell at her because of what she said to me in the message plus he found guys messages in her phone (asking her about cl). Then he took off with her phone and she tried to chase after him but he shut the elevator in her face and ran off with her phone and she tried to chase him to talk about it but it was no use. After about 2 hours of trying to find him, she realized she had no idea where she was. Eventually he found her and took her home and told her that he was going to punish her for what she did and told her to get out. They didnt talk for a few days and she sent him an email telling him she hasn't done anything wrong and shes sorry for calling him names (even though he deserved much more!). He responded with a profanity laced message and told her that he hacked her facebook and deleted every guy on there. She checked and it was true. He told her if she readds them, their relationship is over and he will never speak to her again. I wish I could tell her good-riddance but she honestly does say she loves him. Shes not a gold digger although she does like the attention he gives her. Shes really sweet and she DESERVES better but she seems like she doesn't want to leave him. Why? How can I convince her to break up with him without telling her to break up with him? Shes 19 and in the end the decision is hers and I think its best I let her make her mistakes but its like watching a plane crash only there is something you can possibly do. Sorry for the long question and thanks for reading this far but I wanted to give as much detail as possible. Any advice?